Item image stitching from multiple line-scan images for barcode scanning systems

ABSTRACT

One embodiment of a system and method for imaging items may include storing at least one lookup table that includes position data of multiple image regions, where the position data provides relative positions of the image regions. An item may be moved to pass through the image regions. Image data of the item may be imaged as the item passes through a plurality of the image regions. The position data may be applied to the captured respective image data from each of the image regions through which the item passed to form a set of stitching image data that is substantially aligned with one another. The set of stitching image data may be stitched to form a composite image of the item.

BACKGROUND

Barcode scanning and other imaging systems, such as defect qualitycontrol systems, that use one large view to capture an entire item, suchas product packaging, may use one or more cameras, typically ahigh-resolution line scan camera (e.g., 8192 pixels). However, thesecameras are expensive because of the high-resolution optics and otherhigh-quality camera characteristics. In the event of using multiplebarcode reading cameras or cameras that capture smaller portions of thelarge objects, image stitching may be performed. Conventional imagestitching uses image processing to match features, such as writing orother markings, on the items to align the images captured by eachcamera. As understood in the art, stitching images is computationallytime-consuming and expensive. Moreover, such image processing may be alimiting factor for high-speed object processing, such as manufacturedproducts being moved on high-speed conveyor belts at rates of about 1m/s to about 2 m/s, for example.

With regard to FIG. 1, an illustration of a prior art image stitchingprocess that includes image data 100 of a scene that includes a set ofillustrative line scans 102 a and 102 b (collectively 102) is shown. Thecapture of two line scans 102 in this case is performed by an area imagesensor reading out multiple lines or multiple shorter linear imagesensors that may be used rather than a single image sensor capable ofcapturing the entire scene that is a much more expensive solution. Theline scans 102 a and 102 b are conventionally image processed forstitching the two line scans 102 together using image processing offeatures within the line scans 102 a and 102 b. As an example, imageprocessing may identify a common imaged feature, such as the letter “e”104 a in line scan 102 a and the letter “e” 104 b in line scan 102 b.Other common imaged features may be utilized for the stitching process,as well. The line scans 102 a and 102 b may be stitched by using animage feature stitching process 106 to align the common imaged features104 a and 104 b, as shown by the stitched image 108. In the stitchedimage 108, two grayscale levels 110 a and 110 b show where the two linescans 102 a and 102 b were stitched. In one embodiment, the twograyscale levels 110 a and 110 b may result from different illuminationbeing measured and using two different cameras.

SUMMARY

To overcome the shortcomings of imaging systems that perform barcodescanning or other image processing, one or more cameras that include animage sensor that may be defined into subsets of image pixels thatcapture different portions of a scene may be utilized. Optical devices,such as mirrors, lenses, or otherwise may be used to image a portion ofthe scene (e.g., a certain distance, such as about 7.5 inches, along anX or latitudinal direction of a conveyer belt that is typically 18-24inches wide) onto respective subsets of the image pixels. As an example,two, three, four, or any other number of scene portions may be capturedby an area image sensor separated into multiple views or by multiplecameras with respective image sensors. Usually these types of barcodescanning systems have item dimension measurement sub-systems, eitherincluded in the system or a separated device before a scanning stationor portal with known item dimension and relative line scan viewlocations on the belt by calibration plus the time each line image iscaptured (i.e., the time stamp of each image sensorexposure/integration). Rather than using conventional feature stitching(i.e., matching common features in a scene in the images captured by therespective subsets of pixels of the image sensor, a lookup tableincluding relative position data between line scans captured by thedifferent subsets of pixels may be utilized. In one embodiment, eachsubset of pixels may have an associated lookup table with the possibleexception of one subset of pixels not having an associated lookup tabledue to being defined as a reference or baseline line scan. In analternative embodiment, a single lookup table may include each of theposition relational data for the two or more line scans or scan areasassociated with the subset of pixels. To stitch images together, theimages captured by each of the subsets of pixels may be offset and/orre-oriented without having to image process (e.g., align) imagedfeatures in the data.

One embodiment of a system for imaging items may include a cameraincluding a plurality of imaging pixels, at least one optical elementconfigured and positioned to cause at least two subsets of the imagingpixels to capture respective image regions, and a conveyer beltconfigured to move an item in front of the camera. A non-transitorymemory may be configured to store at least one lookup table thatincludes position data of the image regions, where the position dataprovides relative positions of the image regions. A processing unit maybe in communication with the camera and non-transitory memory, and beconfigured to (i) capture line image data of an item from each of thesubsets of imaging pixels, (ii) apply the position data to the capturedrespective image data from each of the respective subsets of imagingpixels to form a set of stitching image data that is substantiallyaligned with one another, and (iii) stitch the set of stitching imagedata to form a composite image of the item.

A method for imaging items may include storing at least one lookup tablethat includes position data of multiple image regions, where theposition data provides relative positions of the image regions. Theposition data may be determined through a calibration process thatdetermines the position data. An item may be moved to pass through theimage regions. Image data of the item may be imaged as the item passesthrough a plurality of the image regions. The position data may beapplied to the captured respective image data from each of the imageregions through which the item passed to form a set of stitching imagedata that is substantially aligned with one another. The set ofstitching image data may be stitched to form a composite image of theitem.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present invention are described indetail below with reference to the attached drawing figures, which areincorporated by reference herein and wherein:

FIG. 1 is an illustration of a prior art image stitching process thatincludes image data of a scene that includes a set of illustrative linescans;

FIG. 2 is an illustration of an illustrative item processing system inwhich a camera may be configured to capture images to produce image dataof a scene through which items or objects with common height may bemoved by conveyor belt;

FIG. 3 is an illustration of an illustrative multi-pixel image sensor;

FIG. 4A is a scene shown to include a conveyor belt on which an objector item is positioned for movement along a y-axis so as to pass withinscan areas for area scanning that are imaged by a camera with atwo-dimensional (2D) image sensor, such as shown in FIG. 3;

FIG. 4B is an illustration of the scene of FIG. 4A used for linescanning

FIG. 5 is an illustration of an illustrative scanning system, includingan imaging portal of an item or object being imaged by one or morecameras that use multiple scan lines, in this case four line scans;

FIGS. 6A-6C are illustrations of an illustrative scanning and stitchingprocess utilizing multiple cameras to capture image scans used toproduce a stitched image;

FIGS. 7A-7C are illustration of a verification process 700 that showthat the stitching process described herein operates without matchingcommon imaged features;

FIG. 8 is a flow diagram of an illustrative process for stitchingimages;

FIG. 9 is a flow diagram of an illustrative process for stitchingimages; and

FIG. 10 is a flow diagram of an illustrative process for imaging an itemwith known height along a z-axis.

DETAILED DESCRIPTION OF THE DRAWINGS

With regard to FIG. 2, an illustration of an illustrative itemprocessing system 200 in which a camera 202 may be configured to captureimages to produce image data 204 of a scene 206 through which items orobjects 208 with known height in a z-axis may be moved by conveyor belt210 is shown. The item processing system 200 may be a barcode scanningsystem or other image processing system, such as a product inspectionsystem. The items 208 being of known height, may also be common sized,including having substantially the same lengths, widths, and heights.Although the objects 208 are shown to be substantially identical,different sized objects may be processed, but common height objects maybe commonly processed due to the system 200 having to perform imagealignment in the x-direction, as further described herein. The items 208may be moved by a conveyer belt 210 or other moving system (e.g.,robots).

The camera 202 may include a multi-pixel image sensor (see FIG. 3) thatmay be configured to collect scene images and generate the image data204. In one embodiment, one or more optical elements 212 may beconfigured and oriented to cause different portions 214 a and 214 b(collectively 214) of the scene 206 to be imaged onto the image sensorof the camera 202. As an example, the different image portions 214 maybe different linear portions along an x-axis that extends horizontallyacross the conveyer belt 210.

The image data 204 captured by the camera 202 may be communicated to acomputer system 216 for processing thereby. As further described herein,the processing of the image data 204 may include stitching the imagedata 204 (e.g., successive scan lines) without processing imagedfeatures in the image data 204. The image data 204 may be collected inmultiple image streams depending on a number of line scans captured inthe image portions 214 used to capture images across the conveyor belt210, as further described with respect to FIG. 3.

Although the system 200 of FIG. 2 shows a single camera 202, multiplecameras may be utilized. If multiple cameras are utilized, then thecameras or image portions being captured thereby are to be aligned andcalibrated with respect to one another and optionally synchronized intime. By aligning and synchronizing, image data captured by therespective cameras may be stitched by using lookup tables, as furtherdescribed herein. If multiple cameras are used, respective opticaldevice(s) may be utilized to image portions of a scene onto one or moreportions of the respective sensors in the same or similar manner asshown in FIG. 2.

With regard to FIG. 3, an illustration of an illustrative multi-pixelimage sensor 300 is shown. The image sensor 300 is shown to include aplurality of image capture regions 302 a-302 d (collectively 302) thatilluminate corresponding subsets of imaging pixels 304 a-304 d(collectively 304). When image data captured by the subsets of imagingpixels 304 from these image capture regions 302 are stitched together, acomplete image of an image scene, such as image scene 106 of FIG. 1, maybe formed. The image capture regions 302 shown on the image sensor 300are illustrative and in no particular arrangement. It should beunderstood that alternative arrangements and configurations may beutilized. In one embodiment, the size and shape of the image captureregions 302 are substantially identical (e.g., cover the same orsubstantially similar number of pixels). Alternative size and shapes ofthe image capture regions 302 may be utilized, but the same orsubstantially similar number of pixels along a single line or multiplelines of each of the image capture regions 302 may be utilized forstitching an image of the scene together. It should also be understoodthat the actual images that are illuminated on the image sensor 300 mayvary and that sensor data from the subsets of pixels 304 beingilluminated may be collected. Data captured by the subsets of pixels 304may correspond to specific physical locations on the conveyor belt thatmay or may not be physically in line with one another, as shown in FIG.4. Whether or not physically in line with one another, a calibrationprocess may be performed to physically describe the physical positioningwith respect to one of the line scans that operates as a reference linescan. The calibration may result in stitching parameters, such asposition data of each scan area and/or scan line, that may be applied tocaptured image data for stitching the image data from the differentsubsets of imaging pixels.

With regard to FIG. 4A, a scene 400 is shown to include a conveyor belt402 on which an object or item 404 is positioned for movement along ay-axis so as to pass within scan areas 406 a-406 d (collectively 406)that are imaged by a camera with a two-dimensional (2D) image sensor,such as shown in FIG. 3. As shown, the scan areas 406 that are used forarea scanning are misaligned, but overlap in such a manner that a linescan 408 along the x-axis is formed. It should be understood, however,that the scan areas 406 may not be aligned to form the single scan line408, and that a single line scan may be constructed by offsetting thecaptured images of the scan areas 406 on one or more image sensors. Theuse of multiple scan areas 406 enables the use of an inexpensive cameraas compared to a camera capable of scanning across the entire conveyorbelt that may be 24 inches or wider with a sufficient resolution.

With regard to FIG. 4B, the scene 400 of FIG. 4A is shown. However,rather than using scan images to perform area scanning, line scans 410a-410 d (collectively 410) that extend across the conveyor belt 402 maybe used to perform line scanning. The line scans 410 are not in linearalignment with one another, and a stitching process may be used tolinearly align the line scans 410. A calibration may be performed todetermine relative positioning of the line scans 410 with regard to oneanother. The positioning may include linear (shift) alignment in both x-and y-axes, and angular rotation such that the image data captured fromthe scan lines 410 may be linearly aligned. The offsets may be used toform a linear image of the object 404, as captured by the non-linearlyaligned line scans 410. The same or similar process may be used for thescan areas in FIG. 4A.

In addition to stitching parameters, including offsets (shift-X,shift-Y) and rotation of the scan areas 406 (FIG. 3A) and/or line scans410 (FIG. 3B) being stored in lookup tables (see TABLE I as an example),other stitching parameters may be stored in the lookup tables. The otherstitching parameters may include scale ratio and grayscale value. Thescale ratio may be based on distance of the camera (i) from the surfaceof the conveyor belt 402 offset by a height (z-axis) of the items beingimaged or (ii) from a top surface of the item 404 directly. Thegrayscale value may be a predetermined grayscale that is established bya calibration process. In one embodiment, the camera may be calibratedto a given white level utilizing any calibration process as understoodin the art. In the case of using multiple cameras, grayscale levels maybe different for each of the cameras. The grayscale value may calibrateone camera with respect to another camera, one image sensor with respectto another image sensor, and/or one subset of image pixels with respectto another subset of image pixels.

TABLE I Lookup Table H (Height) Shift-X Shift-Y Grayscale Scale Rotationmm pixels pixels Ratio (X) Ratio Degrees 5 10 15 . . . 455 460

Each set of line scans has a table relative to one of the line scans. Asan example, if there are four line scans, then a first line scan (e.g.,left-most line scan) may be a base line scan from which each of theother line scans have lookup tables with stitching parameters that arerelative to the base line scan. In one embodiment, the stitchingparameters are relative stitching parameters. In another embodiment, thestitching parameters are absolute stitching parameters from whichrelative distance, angle, etc., may be calculated. Shift-Y provides foradditional to alignment by timestamp of a line image readout. Theshift-Y may provide for offsetting distance of image data along they-axis during the stitching process. Time stamps may be used if multiplecameras are used such that y-axis offsets may be determined for theShift-Y parameter. The grayscale depends on the illumination ofdifferent optical views and may be compensated by software or lenses maybe grouped and sorted in a similar effective focal length. Rotationangle may be minimized during manufacturing.

With regard to FIG. 5, an illustration of an illustrative scanningsystem 500, including an imaging portal 502 of an item or object 504being imaged by one or more cameras that use multiple scan lines 506a-506 d (collectively 506), in this case four line scans. The line scans506 may be established using optical devices to image a top surface 508of the item 504. As the item 504 has a predetermined height H, thecamera and line scans may be calibrated for the distance from the camerato the top surface 508. As shown, the line scans 506 are aligned toextend across the entire imaging portal 502, thereby allowing the item504 to be positioned anywhere within the scan portal 502 and in anyorientation. In this case, line scans 506 b-506 d completely image thetop surface 508 of the item 504, so that images from these three linescans 506 b-506 d may be used for the imaging process. However, ratherthan performing image processing using image content captured by thethree line scans 506 b-506 d, stitching of the image content captured bythe three line scans 506 b-506 d may be performed by using data storedin three lookup tables associated with the three line scans 506 b-506 d.

As previously described, the data stored in the lookup table may becalibration data and include shift-X, shift-Y, grayscale, scale ratio,and rotation. The three lookup tables include stitching parameters orposition data that, at least in part, describe physical relationships ofthe line scans 506 relative to one another. As an example, the datastored in the lookup tables for line scans 506 b-506 d may includeoffset data that defines relative physical position of each of the linescans 506 b-506 d on the conveyor belt or top surface of items beingscanned relative to line scan 506 a and, consequently, relative to oneanother. For purposes of this description, absolute position dataprovides for relative positioning data and is considered to beequivalent.

With regard to FIGS. 6A-6C, illustrations of an illustrative scanningand stitching process 600 a-600 c utilizing multiple cameras to captureimage scans 602 a and 602 b used to produce a stitched image 602 c areshown. The image scans 602 a and 602 b may be captured by two camerasthat are configured to capture a portion of a scene through which itemsare passed. In this case, a cereal box having a known height in thez-axis is scanned. If multiple cameras are used to capture a portion ofthe scene, then no additional optics elements may be used since thesub-scenes being captured by the respective cameras may be sized in amanner that sufficient resolution may be captured by each of thecameras. In an alternative embodiment, additional optical elements maybe utilized to capture different sub-portions of the scene, aspreviously described. In this case, each of the cameras capturesdifferent aspects of a sub-portion of the scene. For example, and asshown, images 602 a and 604 a may be captured by a first camera byimaging the respective scene portions on different parts of an imagesensor using optical elements, and images 602 b and 604 b may becaptured by a second camera by imaging the respective scene portions ondifferent parts of an image sensor using optical elements. The images602 a and 604 a have different magnifications.

It can be seen that the grayscale levels of the first image scan 602 aand of the second image scan 602 b are different as a result ofillumination and camera/image sensor differences. As previouslydescribed, the images may be captured using scan area imaging or linescan imaging, and lookup table(s) may be used to provide for stitchingthe image scans 602 a and 602 b (or image scans 604 a and 604 b) to formthe stitched image 602 c. As further previously described, rather thanimage processing the image data itself, relative position andorientation (angle) data may be stored in a lookup table that allows forthe two image scans 602 a and 602 b to be stitched by aligning the imagedata captured by the respective cameras (or subset of pixels of thecameras) into a composite image (i.e., an image formed from all or someof the image data from the two image scans, in this case image scans 602a and 602 b). In addition to offsetting one of the image scans 602 b,for example, with respect to the other image scan 602 a, grayscalelevels may also be offset for the different image scans 602 a and 602 b.

With regard to FIGS. 7A-7C, illustrations of a verification process 700show that the stitching process described herein operates withoutmatching common imaged features. As shown, a first verification image702 a and a second verification image 702 b illustrate a capturedportion of an item (e.g., cereal box) may be captured with a centerportion of an item being covered by a piece of paper. The firstverification image 702 a includes image data of a first portion 704 a ofthe item and first center portion 706 a covered by the paper. The secondverification image 702 b includes image data of a second portion 704 bof the item and second center portion 706 b covered by the paper.Because the center portions 706 a and 706 b are covered by the paper, nocommon imaged features of the item are available to process forstitching purposes. Hence, the stitching process is proven to relycompletely on the use of lookup tables, which are defined from acalibration process in aligning line scan locations relative to oneanother, that are used to realign the first and second portions 704 aand 704 b of the item. FIG. 7C shows an illustrative composite image 702c inclusive of the first verification image 702 a and secondverification image 702 b. The composite image 702 c may be formed byoffsetting the first verification image 702 a relative to the secondverification image 702 b.

With regard to FIG. 8, a flow diagram of an illustrative process 800 forstitching images is shown. The process may be used for items of knownheight along a z-axis. The items may be moved along a conveyer belt orother mechanism that may be used to move the times. At step 802, imagesmay be aligned in a y-axis direction by a timestamp. The images may beimages of subsets of imaging pixels of one or more cameras. At step 804,stitching parameters may be loaded from a lookup table. Using thestitching parameters, the images may be adjusted and stitched togetherto form a composite image. In adjusting the images, each of the imagesmay be rotated and moved along the x-axis and y-axis. As previouslydescribed, the stitching parameters may be position data of a scan areaor line scan relative to a reference scan area or line scan.

With regard to FIG. 9, a flow diagram of an illustrative process 900 forstitching images is shown. The process may be used for items of knownheight along a z-axis. The items may be moved along a conveyer belt orother mechanism that may be used to move the times. At step 902, imagesmay be aligned in a y-axis direction by a timestamp. The images may beimages of subsets of imaging pixels of one or more cameras. At step 904,stitching parameters may be loaded from a lookup table. At step 906, apre-defined range of different parameter values may be tried. Thepredefined range is based on calibration, such as lookup table data+/−10pixels in X and Y shifts. At step 908, a difference along a stitchingline may be calculated. At step 910, a minimum may be found to determineoptimal stitching parameters.

With regard to FIG. 10, a flow diagram of an illustrative process forimaging an item with known height along a z-axis is shown. The process1000 may start at step 1002, where at least one lookup table thatincludes position data of multiple image regions may be stored. Theposition data may provide relative positions of the image regions. Theimage regions may be scan areas or scan lines. The image regions may beimaged onto one or more pixel sensors. The relative positions mayinclude position offsets from a reference image region. At step 1004, anitem may be moved to pass through the image regions. The item may bemoved using a conveyer belt, for example. At step 1006, image data ofthe item may be captured as the item passes through a plurality of theimage regions. At step 1008, the position data may be applied to thecaptured respective image data from each of the image regions throughwhich the item passed to form a set of stitching image data that issubstantially aligned with one another. In being substantially aligned,the alignment may be across a linear scan line across the y-axis (andalong the x-axis) as a result of the individual scan lines (or scanareas) being offset and, optionally, rotated. At step 1010, the set ofstitching image data may be stitched to form a composite image of theitem.

The foregoing method descriptions and the process flow diagrams areprovided merely as illustrative examples and are not intended to requireor imply that the steps of the various embodiments must be performed inthe order presented. As will be appreciated by one of skill in the artthe steps in the foregoing embodiments may be performed in any order.Words such as “then,” “next,” etc. are not intended to limit the orderof the steps; these words are simply used to guide the reader throughthe description of the methods. Although process flow diagrams maydescribe the operations as a sequential process, many of the operationscan be performed in parallel or concurrently. In addition, the order ofthe operations may be re-arranged. A process may correspond to a method,a function, a procedure, a subroutine, a subprogram, etc. When a processcorresponds to a function, its termination may correspond to a return ofthe function to the calling function or the main function.

The various illustrative logical blocks, modules, circuits, andalgorithm steps described in connection with the embodiments disclosedherein may be implemented as electronic hardware, computer software, orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the principles ofthe present invention.

Embodiments implemented in computer software may be implemented insoftware, firmware, middleware, microcode, hardware descriptionlanguages, or any combination thereof. A code segment ormachine-executable instructions may represent a procedure, a function, asubprogram, a program, a routine, a subroutine, a module, a softwarepackage, a class, or any combination of instructions, data structures,or program statements. A code segment may be coupled to another codesegment or a hardware circuit by passing and/or receiving information,data, arguments, parameters, or memory contents. Information, arguments,parameters, data, etc. may be passed, forwarded, or transmitted via anysuitable means including memory sharing, message passing, token passing,network transmission, etc.

The actual software code or specialized control hardware used toimplement these systems and methods is not limiting of the invention.Thus, the operation and behavior of the systems and methods weredescribed without reference to the specific software code beingunderstood that software and control hardware can be designed toimplement the systems and methods based on the description herein.

When implemented in software, the functions may be stored as one or moreinstructions or code on a non-transitory computer-readable orprocessor-readable storage medium. The steps of a method or algorithmdisclosed herein may be embodied in a processor-executable softwaremodule which may reside on a computer-readable or processor-readablestorage medium. A non-transitory computer-readable or processor-readablemedia includes both computer storage media and tangible storage mediathat facilitate transfer of a computer program from one place toanother. A non-transitory processor-readable storage media may be anyavailable media that may be accessed by a computer. By way of example,and not limitation, such non-transitory processor-readable media maycomprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage,magnetic disk storage or other magnetic storage devices, or any othertangible storage medium that may be used to store desired program codein the form of instructions or data structures and that may be accessedby a computer or processor. Disk and disc, as used herein, includecompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk, and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media. Additionally, the operations of a method oralgorithm may reside as one or any combination or set of codes and/orinstructions on a non-transitory processor-readable medium and/orcomputer-readable medium, which may be incorporated into a computerprogram product.

The preceding description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the following claims and theprinciples and novel features disclosed herein.

The previous description is of a preferred embodiment for implementingthe invention, and the scope of the invention should not necessarily belimited by this description. The scope of the present invention isinstead defined by the following claims.

What is claimed:
 1. A system for imaging items, said system comprising:a camera including a plurality of imaging pixels; at least one opticalelement configured and positioned to cause at least two subsets of theimaging pixels to capture respective image regions; a conveyer beltconfigured to move an item in front of said camera; a non-transitorymemory configured to store at least one lookup table that includesposition data of the image regions, the position data providing relativepositions of the image regions; a processing unit in communication withsaid camera and said non-transitory memory, and configured to: captureimage data of an item from each of the subsets of imaging pixels; applythe position data to the captured respective image data from each of therespective subsets of imaging pixels to form a set of stitching imagedata that is substantially aligned with one another; and stitch the setof stitching image data to form a composite image of the item.
 2. Thesystem according to claim 1, wherein the at least one lookup tableincludes a distinct lookup table associated with each subset of imagingpixels above one.
 3. The system according to claim 1, wherein the atleast one lookup table includes shift-X, shift-Y, and rotational dataelements that define relative position and angular rotation of thecaptured image data from a first subset of imaging pixels relative toother captured image data from a second subset of imaging pixels.
 4. Thesystem according to claim 3, wherein the at least one lookup tablefurther includes a scale ratio data element.
 5. The system according toclaim 3, wherein the at least one lookup table further includes agrayscale ratio data element.
 6. The system according to claim 5,wherein said processing unit is further configured to apply thegrayscale ratio data element to the captured image data by therespective at least one subset of imaging pixels.
 7. The systemaccording to claim 1, wherein said processing unit, in applying theposition data to the captured image data from each of the respectivesubsets of imaging pixels, is configured to apply the position data toall but one of the captured image data.
 8. The system according to claim1, wherein said processing unit is further configured to calibrate theat least two subsets of the imaging pixels including populating the atleast one lookup table with the position data.
 9. The system accordedclaim 1, wherein said system includes a plurality of cameras including aplurality of imaging pixels, and wherein the at least one lookup tableincludes position data for at least one subset of imaging pixels of eachof the cameras.
 10. The system according to claim 1, wherein the atleast one lookup table include a grayscale value used to adjustgrayscale levels of captured image data by imaging pixels of arespective camera.
 11. A method for imaging items, said methodcomprising: storing at least one lookup table that includes positiondata of multiple image regions, the position data providing relativepositions of the image regions; moving an item to pass through the imageregions; capturing image data of the item as the item passes through aplurality of the image regions; applying the position data to thecaptured respective image data from each of the image regions throughwhich the item passed to form a set of stitching image data that issubstantially aligned with one another; and stitching the set ofstitching image data to form a composite image of the item.
 12. Themethod according to claim 11, wherein storing the at least one lookuptable includes storing a distinct lookup table associated with eachsubset of imaging pixels above one.
 13. The method according to claim11, wherein storing the at least one lookup table includes storingshift-X, shift-Y, and rotational data elements that define relativeposition and angular rotation of the captured image data from a firstsubset of imaging pixels relative to other captured image data from asecond subset of imaging pixels.
 14. The method according to claim 13,wherein storing the at least one lookup table includes storing a scaleratio data element in the at least one lookup table.
 15. The methodaccording to claim 13, wherein storing the at least one lookup tablefurther includes storing a grayscale ratio data element in the at leastone lookup table.
 16. The method according to claim 15, furthercomprising applying the grayscale ratio data element to the capturedimage data by the respective at least one subset of imaging pixels. 17.The method according to claim 11, wherein applying the position data tothe captured respective image data includes apply the position data toall but one of the captured image data.
 18. The method according toclaim 11, further comprising calibrating by populating the at least onelookup table with the position data.
 19. The method accorded claim 11,wherein storing the at least one lookup table includes storing the atleast one lookup table in relation to respective multiple camerasconfigured to image the image regions.
 20. The method according to claim11, wherein storing the at least one lookup table includes storing agrayscale value used to adjust grayscale levels of captured image data.